7mm Jan's 7mm Workbench

Discussion in 'Area 51' started by Lyndhurstman, 1 May 2017.

  1. Lyndhurstman

    Lyndhurstman Western Thunderer

    When Will He Learn?
    Not content with creating mayhem in miniature alongside the Thames, Your Humble Scribe has been encouraged to dip his Size 12's in the eye-soothing largesse of 7mm.

    The first foray is (or rather are) courtesy of Tim Crockford, whose generosity of spirit and support I gratefully acknowledge.

    The beasts in question are a pair of LNER Single Bolsters, courtesy of PMK (PMK 25).

    As the Engineering Dept has spent over half a lifetime in the smaller scales (progressing through OO to EM, before finally settling in the satisfyingly as-correct-as-is-practicable dimensions of P4) most of the hand tools accrued are transferable to the larger scale. However, as this was a suck it and see exercise, the decision was taken not to over-extend an already-stretched budget in the direction of some proper bending bars (such as the wonderful Hold & Fold), and we therefore undertook the construction of a lightweight (aluminium) simulacrum, supported (may we say 'bolstered'? ) by a 2" H&F for 'finishing'.

    So far, so good. The first step - the folding up of the tray of the wagon body - has gone pretty well.
    The first joint:
    IMG_3316.JPG
    In line with the SIAS mindset mentioned above, we're using a cheap-as-chips slightly blunt centre punch for pushing out the rivets (palm pressure only onto a double thickness of cutting mat). and I think it looks OK.
    IMG_3322.JPG
    ... at least, through my rose-tinted glasses.

    Cheers

    Jan
     
    Last edited: 1 May 2017
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  2. Martin Shaw

    Martin Shaw Western Thunderer

    Jan
    I've got the self same kits(s) awaiting further attention. Since you appear to be rather better at this than me, I'll be interested to see how you get on.
    Regards
    Martin
     
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  3. Lyndhurstman

    Lyndhurstman Western Thunderer

    Hi Martin
    I doubt I'm better than anyone! I'm very ham-fisted. But welcome on the journey.

    I think I'll be making one, and then the other. Because I'm intrigued to see if I learn anything along the way!

    Cheers

    Jan
     

    Attached Files:

  4. Lyndhurstman

    Lyndhurstman Western Thunderer

    Bend Sinister
    A bit more advancement yesterday evening.
    20170501_162923663_iOS.jpg
    Here - in all its gawdy gimcrackery (and potentially a 'don't do what I do' for @Martin Shaw :) ) is the cheapskate configuration employed in the folding of one solebar.
    • The first - bottom - bend was made using the bending bars 'right way up'.
    Lesson 1: initial tests identified that the aluminium angle (sourced from The Big Orange Shed) is less than rigid in the middle of the pitch between screws, and so the mini-vice was employed to provide security while finger pressure was applied along the length of the solebar to make the bend). A new set of bars from MS angle might be constructed.

    The right angle was finished off with the 2" H&F and 'AGBE' reckoning.
    • The bars were then turned upside down, and the second bend made.
    This is where the aluminium angle is still useful. Its thin cross-section makes the access easier. If MS angle were used, this might not be possible, as the section has a curved edge. Again, finger pressure was used to perform the bend.

    The result:
    20170501_192857395_iOS.jpg
    Happiness :) (I'm fully aware of what comes before a fall, so I'm giving those particular coordinates a wide berth :thumbs:).

    Cheers

    Jan
     
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  5. Martin Shaw

    Martin Shaw Western Thunderer

    Actually Jan I rather wish you had shown me this before I bent up the solebars, as your's are definitely better than mine.
    IMG_0235.JPG
    Regards
    Martin
     
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  6. Lyndhurstman

    Lyndhurstman Western Thunderer

    Hi Martin

    I've only done one! Plenty of time left to achieve Solebar FUBAR ;)

    Yours look good. Once everything's right way up, there'll be nowt to see. That's what I keep telling myself...

    I'm a bit trepidatious about soldering the fingers - mostly in getting them flat; I'll have to resort to solder paint there. I think.

    Cheers

    Jan
     
  7. Martin Shaw

    Martin Shaw Western Thunderer

    Jan

    I found the easiest way was to apply flux, and then using the tip of a screwdriver to hold the solebar in place, tack solder in 3 or 4 places and then, when happy with the positioning, seam solder the joint. Nothing at all revolutionary about this, and it's not the only way to approach it, but it does work. As you say upside down does rather expose things not normally seen.
    Regards
    Martin
     
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  8. jonte

    jonte Western Thunderer

    So that's how it's done, Jan.

    Very neat.

    Stands back in admiration!

    Bestest,

    Jonte
     
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  9. Lyndhurstman

    Lyndhurstman Western Thunderer

    Beam Me Up
    Saturday afternoon, so it's only logical we have a bit of wrestling to report upon.
    D88CA887-1E57-4B8A-84BF-CA93439B4ECF.jpg
    After a little bit of a song and a dance, the bufferbeams have been fixed in place. As the fit of the solebars between the beams is so precise, a degree of fixing and unfixing was required to enable the solebars to lie flat upon the underside of the body tray. A deal of Carr's Red, and the 40W Antex were required. I think 40W might not be big enough for large flat surfaces. So I may have to bring in the Mignon Models RSU in future builds. Which will mean short interlude for training, as it's been sat in a box for about 25 years!

    The bufferbeam face will be tweaked back toward vertical before the attachment of the solebars.

    Cheers

    Jan
     
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  10. Scale7JB

    Scale7JB Western Thunderer

    Nowt wrong with a 40 Watt for that so long as the tip is big enough to hold some residual heat.

    JB.
     
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  11. Lyndhurstman

    Lyndhurstman Western Thunderer

    Hi JB
    Ta for the enlightenment. I'll have to get a bigger tip, then. The 40W Antex is a bugger to wield as it is, because of the inflexibility of its cable (it may be because I'm cack-handed, of course!). My 25W Weller has a lovely cable that permits - and tolerates - all sorts of intimate cavorting.

    It's all learning. Which is good.

    Cheers

    Jan
     
  12. phileakins

    phileakins Western Thunderer

    +1 for the RSU. Instant adjustable heat exactly where you need it - assuming that you've stuck the probe in the right place that is.

    Bit of a new paradigm as you need to think about grounding the workpiece before you start, but that soon comes with practice. Holding a piece in mid-air wondering why nothing is happening at the 'hot' end is very instructive. :rolleyes:

    Can't be used to carry solder to the joint, so that's a plus as well! Also - big plus, the probe can hold bits in place whilst current is applied and can continue to hold while the solder cools in the joint when the current is off. Can't do that with a Weller. :)
     
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  13. Lyndhurstman

    Lyndhurstman Western Thunderer

    Hi Phil
    Thanks! I'm deffo going to have to give it a go. I was trying to find a suitable chunk of material as baseplate, but the EM Gauge site says a bit of sheet fixed to some MDF will do, so it's looking sooner rather than later for firing up the RSU.

    Cheers

    Jan
     
  14. phileakins

    phileakins Western Thunderer

    Hi Jan

    A steel baseplate is good in the long run - you can use magnets to hold things and the ground wire can be permanently wired in. BUT - in the first instance a piece of baking foil will do just as well. In fact I use baking foil (left over from the Christmas turkey) sacrificially on top of my steel baseplate (scrounged from the good's shed at Swanage) in an attempt to keep it clean!

    Wrap some foil around/on a wooden former/plank and ground it using whatever your PSU provides (crocodile clip?) and Robert's your aunt's paramour - easy and above all cheap and easily replaceable - unlike a hunk of steel; unless you have one readily to hand of course.

    Did I mention cheap? :D
     
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  15. adrian

    adrian Flying Squad

    Personally I found for 7mm kits you do need an 80W iron minimum, especially for large brass platework. My Dad used to have a large 150W iron which was perfect for these jobs it also did an admiral job keeping the workshop warm in the winter months.:D

    For etched brass kits I wouldn't even countenance using a 25W - you just won't get the heat into the job so avoid if at all possible. My 25W iron is reserved for soldering wires and tinning whitemetal castings.

    Sorry but I'm going to disagree here - I'm a -1 for the RSU. For various reasons - which I really do need to publish at some point. IMHO the RSU is great for the job it was originally developed for adding lost wax brass castings to HO brass locos. Adding small details is one of the benefits of an RSU but it is not the universal panacea for soldering that some purport.

    Agreed but there are other ways of achieving the same result with a standard iron. The major problem I have with some advocates of RSU is that they have a setup with a steel earthing plate and then use magnets and all sorts of other clamps to hold the components together. Soldering is a very simple process but a fundamental part of the process is all about getting heat into the joint so to start sticking components on a dirty great big heat sink just seems crazy to me. Yes it appears to work for some people but to me it's success in the face of adversity - surrounded the job with various heatsinks is just making the task harder than it needs to be.
     
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  16. simond

    simond Western Thunderer

    Or just roll up a bit of scrap brass etch, to fit the 4mm plug on your ground wire, and solder it to your vehicle somewhere it won't show. You can whip it off, on, change the angle, whatever.

    RSU's are very versatile. They are not at all a panacea, but they are damn handy.

    Best
    Simon
     
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  17. phileakins

    phileakins Western Thunderer


    I hear what you say Adrian but an RSU is ideally suited for quickly putting easily and readily adjusted heat into a point where solder adhesion is required.

    I agree that it is not a soldering panacea, but nor do I recognise your description of the technique. As I have pointed out to Jan, a piece of baking foil will substitute for the convoluted set-ups you describe. However, what you describe has nothing whatsoever to do with heat dissipation/sinking and more to do with ensuring good electrical grounding and work holding.

    I have quite successfully held a part in my fingers and comfortably soldered it to another, owing to the fact that instantaneous heat is allied where needed, not spread about the neighbourhood to un-stick other stuff or singe the fingers as long as the workpiece was grounded. ;)

    I don't use a heat-sink - I don't need one. The heat is instantaneously applied at the point of application when current flows and equally as instantaneously removed without moving the probe when current stops flowing so allowing the solder to cool.

    Find an RSU and have a go - you might be pleasantly surprised.

    PS Perhaps I should add for those who have no experience of an RSU - the clue is in the name: Resistance Soldering Unit. The heat to melt the solder comes from the resistance to the current from the probe in contact to the solder, to ground. For it to work there must be an electrical circuit.
     
    Last edited: 6 May 2017
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  18. Scale7JB

    Scale7JB Western Thunderer

    Ooh another controversial how to solder thread..

    Only a quick reply.. My entire arsenal is a 25W Antex - 40W Weller and an RSU. Think I've used my 80w once when I was soldering some solid home milled horn guides made from 4mm thick brass. That took a bit of heat, but personally I've never wanted for more than the 40w. Horses for courses and all that.

    JB.
     
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  19. adrian

    adrian Flying Squad

    My apologies for not being clear enough - this was that sort of thing I was alluding to Resistance Soldering because unfortunately quite a few people use this as the "reference" material for resistance soldering when I consider this to be quite misguided information.

    For example from that site
    Sorry but that is quite frankly laughable - as a definition it is so far wide of the mark it's ridiculous. Soldering is a simple mechanical process so we are not persuading, there is no urging or prevailing to be done, we are not trying to reason with the metal and convince it to stick to another component. "frequently dissimilar"???? I would suggest that 99% of the time it is similar metal, either two etched brass components, or nickel silver. Dissimiliar occasionally when adding whitemetal components - although I have yet to see any one demonstrate the addition of whitemetal components with an RSU - although happy to be proved wrong. Finally what's with the stick together at room temperature bit? Sorry but that definition is more applicable to using a bit of superglue than soldering.

    A little bit of background might be appropriate then. I first came across RSUs in 1984, at that time Lord Gretton (Stapleford Park Miniature Railway) turned up at my Dads with various Japanese built HO Brass American Locos and amazed at the detail and being curious as to how they could build them we started investigating. This led to an article on Resistance Soldering and getting information from NorthWest Shortlines (my Dad was importing Sagami motors from them at the time). So in 1985 my Dad commissioned a batch of transformers from a firm in Nottingham and I built a batch of 25 RSUs - at the time we couldn't find an affordable electrical foot switch to cope with the current so we used a pneumatic foot switch from RS. These were sold under the Cherry Scale Models banner - check the Guild archive Volume 9 issue 8 Autumn 1985. We sold it as the "Hot Spot Soldering Unit". They were all built by me as my Dad was an electrical numpty - he once put up a shelf in the workshop and there was a wire in the way so he just cut it out. Bob Moore turned up at lunchtime for their usual Saturday business meeting (in the pub!!) wondering why he wasn't answering his phone! Guess which wire he'd cut!!
    Screen Shot 2017-05-07 at 00.06.09.png

    I subsequently "acquired" a London Road Models RSU. Quite frankly it sat on the workbench gathering dust because there was nothing it could do that wasn't far easier and quicker with using a standard Weller iron. I have since upgraded to an ERSA RDS-80 and this was money well spent and the RSU went up on ebay. For example this 2mmFS cattle wagon was built using the RDS-80 LNWR Special Cattle Wagon - Cherry Clan

    So my apologies for the long reply - but it's safe to say I have had a go with an RSU and it's not for me - as they say your mileage may vary.

    In reply to your comment I would respond with find a silversmithing course at a local college and give it a go. I did and learning how to silver solder in my opinion is invaluable.
     
    Last edited: 7 May 2017
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  20. Scale7JB

    Scale7JB Western Thunderer

    Lovely Adrian, i'm surprised the heat from the 80W didn't buckle the etches..

    JB.